The 2021 demand and supply curves for softwood lumber in Canada are as follows:

P = $ 300 - Q_D ^{Can +Potts} (1)

P = $ 60 + 2Q_S ^Can (2)

where Q_D ^{Can +Potts} is the demand in Canada by Canadian and Pottsvillian consumers for softwood lumber.

As a result of softwood producers lobbying by Pottsvillian producers, in 2022 Pottsville will no longer purchase Canadian softwood. The Pottsvillian demand for Canadian softwood is given by

P = 240- 2Qd^Potts (10)

What are the economic effects of US softwood no longer being sold in Canada?